The origins of economic behavior remain unresolved-not only in the social sciences but also in AI, where dominant theories often rely on predefined incentives or institutional assumptions. Contrary to the longstanding myth of barter as the foundation of exchange, converging evidence from early human societies suggests that reciprocity-not barter-was the foundational economic logic, enabling communities to sustain exchange and social cohesion long before formal markets emerged. Yet despite its centrality, reciprocity lacks a simulateable and cognitively grounded account. Here, we introduce a minimal behavioral framework based on three empirically supported cognitive primitives-individual recognition, reciprocal credence, and cost--return sensitivity-that enable agents to participate in and sustain reciprocal exchange, laying the foundation for scalable economic behavior. These mechanisms scaffold the emergence of cooperation, proto-economic exchange, and institutional structure from the bottom up. By bridging insights from primatology, developmental psychology, and economic anthropology, this framework offers a unified substrate for modeling trust, coordination, and economic behavior in both human and artificial systems. For an interactive visualization of the framework, see: https://egil158.github.io/cogfoundations-econ/

You see a cat chasing a mouse. You probably don't realize it, but as soon as you catch sight of this scene unfolding, your brain makes a key distinction between the cat and the mouse: It identifies who's chasing, and who's being chased. This capacity to distinguish between the "agent" (the entity performing an action) and the "patient" (the entity upon which that action is being performed) is called "event decomposition," and it's long been thought that it was unique to humans. However, a new study published in PLOS Biology on November 26 suggests that this is not the case: great apes (specifically gorillas, chimpanzees, and orangutans) also seem to track events in the way that we do, distinguishing between agent and patient. This finding is notable because scientists believe event decomposition lies at the heart of something that is unique to humans.